Voltage regulator module

ABSTRACT

A voltage regulator module is provided. The switch circuit assembly includes two switch circuits and an input capacitor. Respective input terminals of the two switch circuits are connected with each other in parallel. The input capacitor is electrically connected with the respective input terminals of the two switch circuits in parallel and disposed between the two switch circuits. The plurality of conductive members have a first conductive member, a second conductive member and a third conductive member. The first conductive member and the third conductive member are configured to deliver an electric energy. The second conductive member is configured to deliver a signal. One end of each conductive member is electrically connected with corresponding switch circuit, and the other end of the first conductive member and the third conductive member is electrically connected with the load. The switch circuit assembly and the magnetic assembly are stacked with each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Continuation Application of U.S. patentapplication Ser. No. 16/810,406 filed on Mar. 5, 2020 and entitled“VOLTAGE REGULATOR MODULE”, which claims priority to China patentapplication No. 201910205050.6 filed on Mar. 18, 2019. The entireties ofthe above-mentioned patent applications are incorporated herein byreference for all purposes.

FIELD OF THE INVENTION

The present disclosure relates to a voltage regulator module, and moreparticularly to a voltage regulator module with reduced volume.

BACKGROUND OF THE INVENTION

Please refer to FIGS. 1A and 1B. FIG. 1A schematically illustrates thestructure of a conventional electronic device. FIG. 1B schematicallyillustrates the structure of a voltage regulator module of theelectronic device as shown in FIG. 1A. As shown in FIGS. 1A and 1B, theelectronic device 1 has a horizontal layout structure. The electronicdevice 1 includes a central processing unit (CPU) 11, a voltageregulator module 12, a system board 13 and an output capacitor 14. Thevoltage regulator module 12 is used for converting an input voltage intoa regulated voltage and providing the regulated voltage to the centralprocessing unit 11. The system board 13 has a first surface and a secondsurface, which are opposed to each other. The voltage regulator module12 and the central processing unit 11 are disposed on the first surfaceof the system board 13. For meeting the load dynamic switchingrequirements, the output terminal of the voltage regulator module 12 islocated near the input terminal of the central processing unit 11. Theoutput capacitor 14 is disposed on the second surface of the systemboard 13. The output capacitor 14 is located beside the input terminalof the central processing unit 11.

The voltage regulator module 12 further includes a printed circuit board15 and a magnetic element 16. The magnetic element 16 is disposed on theprinted circuit board 15. Moreover, a switch element is disposed in avacant space between the printed circuit board 15 and the magneticelement 16. The printed circuit board 15 is disposed on the firstsurface of the system board 13. The heat from the voltage regulatormodule 12 can be transferred to the system board 13 through the printedcircuit board 15. Moreover, the heat is dissipated away through a heatdissipation mechanism (not shown) of the system board 13.

Recently, the required current for the central processing unit 11 isgradually increased. In addition, the trend of the volume of theelectronic device is toward miniaturization. Since the centralprocessing unit 11 and the voltage regulator module 12 are located atthe same side of the system board 13, the electronic device cannot meetthe load dynamic switching requirements.

For reducing the volume of the electronic device and effectivelyenhancing the dynamic switching performance of the voltage regulatormodule, another electronic device is disclosed. FIG. 2 schematicallyillustrates the structure of another conventional electronic device. Theelectronic device 1′ of FIG. 2 has the vertical layout structure. Thevoltage regulator module 12 is disposed on the second surface of thesystem board 13, so that the voltage regulator module 12 and the centralprocessing unit 11 are disposed on opposed surfaces of the system board13. Consequently, the volume of the electronic device 1′ is effectivelyreduced. Moreover, since the output capacitor (not shown) is locatednear the output terminal of the voltage regulator module 12 and theinput terminal of the central processing unit 11, the dynamic switchingperformance of the voltage regulator module 12 is enhanced.

Although the dynamic switching performance of the voltage regulatormodule of the electronic device 1′ as shown in FIG. 2 is enhanced, thereare still some drawbacks. For example, since the magnetic element 16 andthe switch element of the voltage regulator module 12 are disposed onthe same side of the printed circuit board 15 and the switch element isdisposed in the vacant space between the printed circuit board 15 andthe magnetic element 16, it is difficult to optimize the structure andthe size of the magnetic element 16 of the voltage regulator module 12.In other words, the size of the voltage regulator module 12 in theelectronic device 1′ is still large. Moreover, when the voltageregulator module 12 on the system board 13 undergoes a reflow solderingprocess, the inner components to be reheated are possibly detached orshifted.

Therefore, there is a need of providing an improved voltage regulatormodule in order to overcome the drawbacks of the conventionaltechnologies.

SUMMARY OF THE INVENTION

An object of the present disclosure provides a voltage regulator modulewith reduced size.

Another object of the present disclosure provides a voltage regulatormodule that is manufactured by a simplified fabricating process.

In accordance with an aspect of the present disclosure, a voltageregulator module is provided. The voltage regulator module powers a loadand includes a switch circuit assembly and a magnetic assembly. Theswitch circuit assembly includes two switch circuits and an inputcapacitor. Respective input terminals of the two switch circuits areconnected with each other in parallel. The input capacitor iselectrically connected with the respective input terminals of the twoswitch circuits in parallel and disposed between the two switchcircuits. The magnetic assembly includes a core assembly and a pluralityof conductive members. The plurality of conductive members have at leastone first conductive member, at least one second conductive member andat least one third conductive member. The at least one first conductivemember and the at least one third conductive member are configured todeliver an electric energy. The at least one second conductive member isconfigured to deliver a signal. One end of each of the plurality ofconductive members is electrically connected with corresponding one ofthe two switch circuits, and the other end of the at least one firstconductive member and the at least one third conductive member of theplurality of conductive members is electrically connected with the load.The switch circuit assembly and the magnetic assembly are stacked witheach other.

In accordance with another aspect of the present disclosure, a voltageregulator module is provided. The voltage regulator module includes aswitch circuit assembly, a magnetic assembly and a conductor assembly.The switch circuit assembly includes a switch circuit. The magneticassembly includes at least one core assembly and at least one firstconductive member. The core assembly has an opening. The at least onefirst conductive member penetrates through the opening. The switchcircuit assembly, the magnetic assembly and the conductor assembly arestacked with each other in sequence. One end of the at least one firstconductive member is electrically connected with corresponding switchcircuit, and the other end of the at least one first conductive memberis electrically connected with the conductor assembly. An inductor isdefined by the at least one first conductive member penetrating throughthe opening and the core assembly collaboratively. The inductor isembedded in a printed circuit board.

The above contents of the present disclosure will become more readilyapparent to those ordinarily skilled in the art after reviewing thefollowing detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A schematically illustrates the structure of a conventionalelectronic device;

FIG. 1B schematically illustrates the structure of a voltage regulatormodule of the electronic device as shown in FIG. 1A;

FIG. 2 schematically illustrates the structure of another conventionalelectronic device;

FIG. 3A is a schematic perspective view illustrating a voltage regulatormodule according to a first embodiment of the present disclosure andtaken along a viewpoint;

FIG. 3B is a schematic perspective view illustrating the voltageregulator module of FIG. 3A and taken along another viewpoint;

FIG. 3C is a schematic exploded view illustrating the voltage regulatormodule of FIG. 3B;

FIG. 4 is a schematic equivalent circuit diagram illustrating thevoltage regulator module of FIG. 3A;

FIG. 5 schematically illustrates a lead frame with the fourth copperposts;

FIG. 6 schematically illustrates the concept of using the lead frame asshown in FIG. 5 to produce a plurality of voltage regulator modules;

FIG. 7A is a schematic perspective view illustrating a package structureof the voltage regulator module according to the embodiment of thepresent disclosure;

FIG. 7B is a schematic perspective view illustrating the packagestructure of the voltage regulator module as shown in FIG. 7A and takenalong another viewpoint;

FIG. 8 is a schematic perspective view illustrating a package structureof a voltage regulator module according to another embodiment of thepresent disclosure;

FIG. 9 is a schematic top cross-sectional view illustrating the innerlayer of the printed circuit board of the voltage regulator module asshown in FIG. 8;

FIG. 10A is a schematic cross-sectional view illustrating the packagestructure of the voltage regulator module as shown in FIG. 8; and

FIG. 10B is a schematic cross-sectional view illustrating a variantexample of the package structure of the voltage regulator module asshown in FIG. 10A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present disclosure will now be described more specifically withreference to the following embodiments. It is to be noted that thefollowing descriptions of preferred embodiments of this disclosure arepresented herein for purpose of illustration and description only. It isnot intended to be exhaustive or to be limited to the precise formdisclosed.

Please refer to FIGS. 3A, 3B, 3C and 4. FIG. 3A is a schematicperspective view illustrating a voltage regulator module according to afirst embodiment of the present disclosure and taken along a viewpoint.FIG. 3B is a schematic perspective view illustrating the voltageregulator module of FIG. 3A and taken along another viewpoint. FIG. 3Cis a schematic exploded view illustrating the voltage regulator moduleof FIG. 3B. FIG. 4 is a schematic equivalent circuit diagramillustrating the voltage regulator module of FIG. 3A. The voltageregulator module 2 may be disposed on an electronic device andelectrically connected with a system board (not shown) within theelectronic device through a welding means. The voltage regulator module2 is at least one phase buck converter and includes at least one switchelements 21, at least one inductor L, at least one input capacitor Cinand at least one output capacitor Cout. For example, the switch element21 is a driver and metal-oxide-semiconductor field-effect transistor(also referred as a Dr.MOS element 21). In case that the centralprocessing unit of the electronic device requires a large amount ofcurrent, the voltage regulator module 2 is a multi-phase buck converter.Consequently, the capability of the voltage regulator module 2 to outputelectricity is effectively enhanced.

In the embodiment of FIG. 4, the voltage regulator module 2 is atwo-phase buck converter. The voltage regulator module 2 includes twoDr.MOS elements 21 and two inductors L. Each Dr.MOS element 21 and afirst terminal SW of the corresponding inductor L are electricallyconnected with each other in series to define a phase buck circuit. Inthis embodiment, the voltage regulator module 2 includes two phase buckcircuits. The input side of the voltage regulator module 2 includes apositive input terminal Vin+and a negative input terminal Vin−. Thefirst terminals of the two phase buck circuits are connected with eachother in parallel and electrically connected with the input capacitorCin. The output side of the voltage regulator module 2 includes apositive output terminal Vo+and a negative output terminal Vo−. Thenegative input terminal Vin− and the negative output terminal Vo− areelectrically connected with a common terminal. The second terminals ofthe two phase buck circuits are connected with each other in paralleland electrically connected with the output capacitor Cout. A firstterminal of the output capacitor Cout is electrically connected with thepositive output terminal Vo+of the voltage regulator module 2. A secondterminal of the output capacitor Cout is electrically connected with thenegative output terminal Vo− of the voltage regulator module 2. A firstterminal of the input capacitor Cin is electrically connected with thepositive input terminal Vin+of the voltage regulator module 2. A secondterminal of the input capacitor Cin is electrically connected with thenegative input terminal Vin− of the voltage regulator module 2.

In an embodiment, each Dr.MOS element 21 includes a switch and a driverfor driving the switch. The voltage regulator module 2 further includesa control circuit D. After the control circuit D samples the outputvoltage of the voltage regulator module 2 and the output current of eachphase buck circuit, the control circuit D generates two pulse widthmodulation signals PWM1 and PWM2. The phase difference between the twopulse width modulation signals PWM1 and PWM2 is 180 degree. The firstphase buck circuit and the second phase buck circuit are controlledaccording to the first pulse width modulation signal PWM1 and the secondpulse width modulation signal PWM2, respectively.

Please refer to FIG. 3C. Structurally, the voltage regulator module 2includes a circuit board assembly 20 and a magnetic core assembly 30.The circuit board assembly 20 includes a printed circuit board 22, atleast one Dr.MOS element 21, at least one first copper post 51, at leastone second copper post 52 and at least one third copper post 53. Theprinted circuit board 22 has a first surface 22 a and a second surface22 b, which are opposed to each other. The printed circuit board 22further includes a lateral wall 22 c, which is arranged between thefirst surface 22 a and the second surface 22 b. All Dr.MOS elements 21and all input capacitors Cin are mounted on the first surface 22 a ofthe printed circuit board 22 by a welding process or through aconductive adhesive (see FIG. 3A). In addition, the input capacitors Cinare electrically connected with the Dr.MOS elements 21. In thisembodiment, the installation directions of the two Dr.MOS elements 21 onthe first surface 22 a of the printed circuit board 22 are opposed.Consequently, the input voltage pins of the two Dr.MOS elements 21 arearranged near each other. The input capacitors Cin are arranged betweenthe two Dr.MOS elements 21. That is, the input capacitors Cin arearranged between the input voltage pins of the two Dr.MOS elements 21.The input capacitors Cin are shared by the two Dr.MOS elements 21.Consequently, instead of routing wire, the nearby input voltage pins ofthe two Dr.MOS elements 21 are electrically connected with the inputcapacitors Cin, and the number of the input capacitors Cin is reduced.

The at least one first copper post 51, the at least one second copperpost 52 and the at least one third copper post 53 are mounted on thesecond surface 22 b of the printed circuit board 22 by a welding processor through a conductive adhesive. A portion of a lateral surface of thesecond copper post 52 and a portion of a lateral surface of the thirdcopper post 53 are coplanar with the lateral wall 22 c of the printedcircuit board 22. The at least one first copper post 51 is used as thepositive output terminal of the voltage regulator module 2. The at leastone second copper post 52 is used as the positive input terminal of thevoltage regulator module 2. The at least one third copper post 53 isused as the negative output terminal of the voltage regulator module 2.

In an embodiment, the circuit board assembly 20 of the voltage regulatormodule 2 further includes at least one fourth copper post 54. Forexample, as shown in FIGS. 3B and 3C, the circuit board assembly 20further includes a plurality of fourth copper posts 54. A portion of alateral surface of the fourth copper posts 54 is coplanar with thelateral wall 22 c of the printed circuit board 22. The plurality offourth copper posts 54 are mounted on the second surface 22 b of theprinted circuit board 22 by a welding process or through a conductiveadhesive. The plurality of fourth copper posts 54 are used as signalterminals of the voltage regulator module 2. When the voltage regulatormodule 2 is welded on a system board (not shown), the voltage regulatormodule 2 is in communication with the system board through the pluralityof fourth copper posts 54.

In an embodiment, the voltage regulator module 2 is welded on the systemboard through the at least one first copper post 51, the at least onesecond copper post 52, the at least one third copper post 53 and the atleast one fourth copper post 54 of the circuit board assembly 20.Consequently, the size of the voltage regulator module 2 is reduced.

The magnetic core assembly 30 is disposed on the second surface 22 b ofthe printed circuit board 22. Moreover, the magnetic core assembly 30includes at least one ring-shaped core 31. In this embodiment, thevoltage regulator module 2 is a two-phase buck converter. In otherwords, the magnetic core assembly 30 includes two ring-shaped cores 31.Each ring-shaped core 31 has a corresponding opening 30 b. When themagnetic core assembly 30 is disposed on the second surface 22 b of theprinted circuit board 22, the first copper posts 51 are penetratedthrough the corresponding openings 30 b. Consequently, two inductors Lare defined by the corresponding first copper posts 51 and the magneticcore assembly 30 collaboratively.

In an embodiment, the magnetic core assembly 30 further includes atleast one air gap 30 c. As shown in FIGS. 3B and 3C, the magnetic coreassembly 30 includes two air gaps 30 c. The two air gaps 30 c are formedin the corresponding ring-shaped cores 31 respectively and located attwo opposite sides of the magnetic core assembly 30. In an embodiment,the two ring-shaped cores 31 of the magnetic core assembly 30 areintegrally formed as an 8-shaped one-piece structure. Alternatively, thering-shaped cores 31 are individual components and combined as themagnetic core assembly 30.

In this embodiment, the opening 30 b of the magnetic core assembly 30has a circular shape. The first copper post 51 also has a circularshape. It is noted that the profiles of the opening 30 b and the firstcopper post 51 are not restricted. For example, the opening 30 b has arectangular shape or any other appropriate shape, and the first copperpost 51 has the shape matching the opening 30 b. An external surface 30d of the magnetic core assembly 30 has a circular shape. Moreover, theshape of the external surface 30 d of the magnetic core assembly 30 isnot restricted.

In an embodiment, some or all of the fourth copper posts 54 arepreviously disposed on a lead frame. Consequently, the lead frame withthe fourth copper posts 54 can be welded on the printed circuit board 22more easily, and the fourth copper posts 54 can be well disposed andpositioned. Similarly, the at least one first copper post 51, the atleast one second copper post 52 and the at least one third copper post53 may be previously disposed on a lead frame so as to increase theinstallation efficiency. Hereinafter, an example of using the lead framewith the fourth copper posts 54 in the manufacturing process of thevoltage regulator module 2 will be illustrated with reference to FIGS. 5and 6.

FIG. 5 schematically illustrates a lead frame with the fourth copperposts. FIG. 6 schematically illustrates the concept of using the leadframe as shown in FIG. 5 to produce a plurality of voltage regulatormodules. As shown in FIG. 5, the fourth copper posts 54 are previouslydisposed on a lead frame 55. The lead frame 55 includes a frame body 56.The fourth copper posts 54 are coupled to the inner periphery of theframe body 56. Since the lead frame 55 with the fourth copper posts 54can be welded on the printed circuit board 22 more easily, theefficiency of installing the fourth copper posts 54 is enhanced. Theabove concept may be expanded to manufacture a plurality of voltageregulator modules 2. Please refer to FIG. 6. In some embodiments, aconnection printed circuit board with a plurality of printed circuitboards 22 is provided. After a plurality of magnetic core assemblies 30are mounted on the corresponding printed circuit boards 22, a pluralityof semi-finished products 4 a of the voltage regulator modules 2 areproduced. Then, a plurality of lead frames 55 are disposed on the secondsurfaces 22 b of the corresponding printed circuit boards 22. Then, thefourth copper posts 54 of each lead frame 55 are welded on the secondsurface 22 b of the printed circuit board 22 of the correspondingsemi-finished product 4 a. Since the fourth copper posts 54 are firstlyfixed by the lead frame 55 and then welded on the corresponding printedcircuit board 22, the fourth copper posts 54 will not be shifted duringthe welding process or in the subsequent process. For example, thefourth copper posts 54 are not shifted in the packaging process. In anembodiment, the at least one first copper post 51, the at least onesecond copper post 52 and the at least one third copper post 53 aredisposed on the second surface 22 b of the corresponding printed circuitboard 22 before the lead frame 55 is welded on the corresponding printedcircuit board 22. In another embodiment, the at least one first copperpost 51, the at least one second copper post 52 and the at least onethird copper post 53 are welded on the second surface 22 b of thecorresponding printed circuit board 22 after the lead frame 55 is weldedon the corresponding printed circuit board 22. Please refer to FIG. 6again. After the plurality of semi-finished products 4 a of the voltageregulator modules 2 are packaged, the junctions between the frame body56 and the fourth copper posts 54 of each semi-finished product 4 a arecut off and the junctions between the adjacent semi-finished products 4a of the connection printed circuit board are cut off. Consequently, aplurality of individual voltage regulator modules 2 are produced.

Please refer to FIGS. 7A and 7B. FIG. 7A is a schematic perspective viewillustrating a package structure of the voltage regulator moduleaccording to the embodiment of the present disclosure. FIG. 7B is aschematic perspective view illustrating the package structure of thevoltage regulator module as shown in FIG. 7A and taken along anotherviewpoint. The voltage regulator module 2 further includes a moldingcompound layer 60. The first surface 22 a of the printed circuit board22, the components on the first surface 22 a of the printed circuitboard 22 (e.g., the Dr.MOS elements 21 and the input capacitors Cin),the second surface 22 b of the printed circuit board 22 and thecomponents on the second surface 22 b of the printed circuit board 22(e.g., the copper posts 51, 52, 53 and 54) are encapsulated by themolding compound layer 60 in a double-sided molding manner. The moldingcompound layer 60 includes a first molding side 60 a, a second moldingside 60 b and a lateral molding wall 60 c. The first molding side 60 aof the molding compound layer 60 and the first surface 22 a of theprinted circuit board 22 are located at the same side of the printedcircuit board 22. The second molding side 60 b of the molding compoundlayer 60 and the second surface 22 b of the printed circuit board 22 arelocated at the same side of the printed circuit board 22. The firstmolding side 60 a and the second molding side 60 b are opposed to eachother. The lateral molding wall 60 c of the molding compound layer 60 isarranged between the first molding side 60 a and the second molding side60 b. In some embodiments, the first molding side 60 a of the moldingcompound layer 60 is milled to adjust the thermal resistances of theheat generation components on the first surface 22 a of the printedcircuit board 22 (e.g., the Dr.MOS elements 21 and the input capacitorsCin). Optionally, after the first molding side 60 a of the moldingcompound layer 60 is milled, the Dr.MOS elements 21 are exposed outsidethe first molding side 60 a of the molding compound layer 60. Theexternal surface of the first molding side 60 a of the molding compoundlayer 60 is a flat surface. The external surface is attached and fixedon a casing or a heat sink of the electronic device. Consequently, thethermal resistance is further reduced, and the heat dissipatingcapability of the voltage regulator module is increased.

Similarly, the second molding side 60 b of the molding compound layer 60is milled. Consequently, the end surfaces of the copper posts 51, 52, 53and 54 are exposed outside the second molding side 60 b of the moldingcompound layer 60 and coplanar with the second molding side 60 b of themolding compound layer 60. Moreover, the exposed portions of the copperposts 51, 52, 53 and 54 may be chemically plated. Consequently, theexposed portions of the copper posts 51, 52, 53 and 54 are used asbonding pads with larger areas.

Please refer to FIGS. 7A and 7B again. A first bonding pad 51 acorresponding to the end surface of the first copper post 51 located inthe second molding side 60 b is used as a positive output terminalconductor of the voltage regulator module 2. The first bonding pad 51 ahas a strip shape in the second molding side 60 b. Moreover, the twoends of the first bonding pad 51 a are connected with two lateral sidesof the lateral molding wall 60 c of the molding compound layer 60.Moreover, two electroplated regions 60 d are formed on the lateral sidesof the lateral molding wall 60 c. When the voltage regulator module 2 onthe system board undergoes a reflow soldering process, the electroplatedregions 60 d can provide lateral wetting capability. Consequently, thewelding strength of the combination between the voltage regulator module2 and the system board is enhanced. Moreover, a second bonding pad 52 acorresponding to the end surface of the second copper post 52 located inthe second molding side 60 b is used as a positive input terminalconductor of the voltage regulator module 2. A third bonding pad 53 acorresponding to the end surface of the third copper post 53 located inthe second molding side 60 b is used as a negative output terminalconductor of the voltage regulator module 2. A fourth bonding pad 54 acorresponding to the end surface of the fourth copper post 54 located inthe second molding side 60 b is used as a signal terminal conductor. Theelectroplated regions 60 d, the second bonding pad 52 a, the thirdbonding pad 53 a and the fourth bonding pad 54 a can increase theoverall area of the bonding pad, reduce the average forces on the solderjoints of the copper posts 51, 52, 53 and 54 and increase the strengthof the solder joints. In addition, the weight withstood by the unitwelding surface is reduced, the purpose of diffusing current isachieved, and the power loss is reduced. Moreover, since the firstmolding side 60 a and the second molding side 60 b of the moldingcompound layer 60 can be milled, the overall height of the voltageregulator module 2 is adjustable. Preferably, the area of the firstbonding pad 51 a (i.e., the positive output terminal conductor) islarger than or equal to the end surface area of the first copper post51, the area of the second bonding pad 52 a (i.e., the positive inputterminal conductor) is larger than or equal to the end surface area ofthe second copper post 52, and the area of the third bonding pad 53 a(i.e., the negative output terminal conductor) is larger than or equalto the end surface area of the third copper post 53.

In an embodiment, the second molding side 60 b of the molding compoundlayer 60 is milled such that a surface of the magnetic core assembly 30is exposed. When the voltage regulator module 2 is welded on the systemboard, the exposed surface of the magnetic core assembly 30 can beattached on the system board directly. Consequently, the heatdissipating capability of the magnetic core assembly 30 is enhanced.

In some embodiments, the lateral molding wall 60 c of the moldingcompound layer 60 is milled. Consequently, portions of the surfaces ofthe copper posts 52, 53 and 54 are exposed outside the lateral moldingwall 60 c of the molding compound layer 60. Moreover, the exposedportions of the surfaces of the copper posts 52, 53 and 54 may bechemically plated. Consequently, the portion of the second copper post52 exposed outside the lateral molding wall 60 c is connected with thesecond bonding pad 52 a (i.e., the positive input terminal conductor),the portion of the third copper post 53 exposed outside the lateralmolding wall 60 c is connected with the third bonding pad 53 a (i.e.,the negative output terminal conductor), and the portion of the fourthcopper post 54 exposed outside the lateral molding wall 60 c isconnected with the fourth bonding pad 54 a (i.e., the signal terminalconductor). When the voltage regulator module 2 on the system boardundergoes a reflow soldering process, the electroplated regions of thecopper posts 52, 53 and 54 can provide lateral wetting capability.Consequently, the welding strength of the combination between thevoltage regulator module 2 and the system board is enhanced.

Please refer to FIGS. 3B and 3C. The circuit board assembly 20 of thevoltage regulator module 2 includes two first copper posts 51 and twosecond copper posts 52. The two first copper posts 51 are located at amiddle region of the printed circuit board 22. The two second copperposts 52 are respectively located beside two sides of the midpoint ofthe two first copper posts 51. The two second copper posts 52 aredisposed on the second surface 22 b of the printed circuit board 22 andsymmetric with respect to the midpoint of the two first copper posts 51.Moreover, the two second copper posts 52 are arranged beside the regionbetween the two first copper posts 51. The circuit board assembly 20 ofthe voltage regulator module 2 includes two third copper posts 53. Thesecond surface 22 b of the printed circuit board 22 has four corners.Two corners are arranged along a first diagonal line and symmetric withrespect to the midpoint of the second surface 22 b of the printedcircuit board 22. The other two corners are arranged along a seconddiagonal line and symmetric with respect to the midpoint of the secondsurface 22 b of the printed circuit board 22. The two third copper posts53 are disposed on the second surface 22 b of the printed circuit board22 and located at the two corners along the first diagonal line,respectively. Moreover, the two third copper posts 53 are respectivelylocated beside two sides of the midpoint of the two first copper posts51. Portion of the plurality of fourth copper posts 54 and the rest ofthe plurality of fourth copper posts 54 are disposed on the secondsurface 22 b of the printed circuit board 22 and located at the twocorners along the second diagonal line respectively. When the voltageregulator module 2 is welded on the system board, the voltage regulatormodule 2 is in communication with the system board through the signalterminals.

In some embodiments, the magnetic core assembly 30 is fixed on thesecond surface 22 b of the printed circuit board 22 through a thermaladhesive. Consequently, the heat dissipating capability of the magneticcore assembly 30 is enhanced. In this embodiments, there is a first gap23 between the external surface 30 d of the magnetic core assembly 30and the second copper post 52 (and the third copper post 53), and thereis a second gap 24 between an inner wall 30 e of the magnetic coreassembly 30 and the first copper post 51. An underfill material isfilled in the first gap 23 and the second gap 24. Consequently, themagnetic core assembly 30, the printed circuit board 22 and the adjacentcopper posts are contacted with each other through the underfillmaterial. Due to the underfill material, no vacant spaces exit in thefirst gap 23 and the second gap 24 after the packaging process iscompleted.

As mentioned above, the voltage regulator module 2 is encapsulated bythe molding compound layer 60 through the double-sided plastic moldingprocess. Moreover, the copper posts 51, 52, 53 and 54 are chemicallyplated to generate the corresponding bonding pads. The bonding pads areelectrically connected with the system board. Consequently, when thevoltage regulator module on the system board undergoes a reflowsoldering process, the inner components to be reheated are not detachedor shifted. In other words, the process of fabricating the voltageregulator module 2 is simplified.

It is noted that the example of the voltage regulator module may bemodified. For example, the magnetic core assembly 30, the first copperposts 51, the second copper posts 52 and the third copper posts 53 areembedded within the printed circuit board 22. Moreover, the secondsurface 22 b of the printed circuit board 22 is electroplated to formthe first bonding pad 51 a (i.e., the positive output terminalconductor), the second bonding pad 52 a (i.e., the positive inputterminal conductor), the third bonding pad 53 a (i.e., the negativeoutput terminal conductor) and the fourth bonding pad 54 a.

FIG. 8 is a schematic perspective view illustrating a package structureof a voltage regulator module according to another embodiment of thepresent disclosure. In comparison with the above embodiment, the printedcircuit board 22 includes an inner layer 80. That is, the printedcircuit board 22 is a multilayered printed circuit board 22. As shown inFIG. 3B, the magnetic core assembly 30 has a top surface 30 f and abottom surface 30 g. After an electroplating process is performed, afirst copper electrode and a second copper electrode are formed on thetop surface 30 f and the bottom surface 30 g, respectively. Moreover,the magnetic core assembly 30, the first copper posts 51, the secondcopper posts 52 and the third copper posts 53 are fixed and embeddedwithin the inner layer 80 of the printed circuit board 22.

FIG. 9 is a schematic top cross-sectional view illustrating the innerlayer of the printed circuit board of the voltage regulator module asshown in FIG. 8. The inner layer 80 includes a switch region 81, amagnetic core region 82, a positive input region 83 and a negativeoutput region 84. The first copper posts 51 are disposed and fixed onthe switch region 81. The magnetic core assembly 30 is disposed andfixed on the magnetic core region 82. The second copper posts 52 aredisposed and fixed on the positive input region 83 and used as thepositive input terminal of the voltage regulator module 2. The thirdcopper posts 53 are disposed and fixed on the negative output region 84and used as the negative output terminal of the voltage regulator module2. In some embodiments, the magnetic core region 82 is connected withthe positive input region 83 to form a connection region. Alternatively,the magnetic core region 82 is connected with the negative output region84 to form a connection region.

In an embodiment, a plurality of plated through-holes corresponding tothe first copper posts 51, the second copper posts 52, the third copperposts 53, the first copper electrode and the second copper electrode areformed in the first surface 22 a and the second surface 22 b of theprinted circuit board 22. The switch region 81, the magnetic core region82, the positive input region 83 and the negative output region 84 areconnected with corresponding pins of the Dr.MOS elements 21, which aremounted on the first surface 22 a of the printed circuit board 22through the corresponding plated through-holes.

FIG. 10A is a schematic cross-sectional view illustrating the packagestructure of the voltage regulator module as shown in FIG. 8. Theprinted circuit board 22 includes first plated through-holes 91 andsecond plated through-holes (PTH) 92. The first copper posts 51 and thecorresponding pins of the Dr.MOS elements 21 on the first surface 22 aof the printed circuit board 22 are electrically connected with eachother through the corresponding first plated through-holes 91. Thesecond copper electrode of the magnetic core assembly 30 and thecorresponding pins of the Dr.MOS elements 21 on the first surface 22 aof the printed circuit board 22 are electrically connected with eachother through the corresponding second plated through-holes 92.Moreover, the printed circuit board 22 includes signal platedthrough-holes (not shown) for connecting the fourth bonding pad 54 awith the corresponding pins of the Dr.MOS elements 21 on the firstsurface 22 a of the printed circuit board 22.

As shown in FIG. 10A, the printed circuit board 22 further includesthird plated through-holes 93 and fourth plated through-holes 94. Thefirst bonding pad 51 a and the first copper electrode of the magneticcore assembly 30 are electrically connected with each other through thecorresponding third plated through-holes 93. The first bonding pad 51 aand the first copper posts 51 are electrically connected with each otherthrough the corresponding fourth plated through-holes 94.

In this embodiment, the plated through-holes 91, 92, 93 and 94 arestraight holes. It is noted that numerous modifications and alterationsmay be made while retaining the teachings of the disclosure. FIG. 10B isa schematic cross-sectional view illustrating a variant example of thepackage structure of the voltage regulator module as shown in FIG. 10A.In the variant example, the plated through-holes 91, 92, 93 and 94 arestepped holes.

Since the copper electrodes are disposed on the top surface and thebottom surface of the magnetic core assembly 30 and the copperelectrodes are electrically connected with the bonding pads through thecorresponding plated through-holes, the interface thermal resistancebetween the magnetic core assembly 30 and the surfaces of the printedcircuit board 22 is reduced. In such way, the heat generated by themagnetic core assembly 30 can be transferred to the surfaces of theprinted circuit board 22 through the corresponding plated through-holesand dissipated away.

Similarly, the second bonding pad 52 a (i.e., the positive inputterminal conductor) is electrically connected with the second copperposts 52 through corresponding plated through-holes (not shown), and thethird bonding pad 53 a (i.e., the negative output terminal conductor) iselectrically connected with the third copper posts 53 throughcorresponding plated through-holes (not shown). In some embodiments, thefourth copper posts are replaced by corresponding signal through-holes(not shown). Moreover, one end of each signal through-hole is contactedwith the corresponding pin of the Dr.MOS element 21, and the other endof each signal through-hole is contacted with the fourth bonding pad 54a.

Moreover, the copper posts 52, 53 and 54 are exposed to the lateralmolding wall 60 c of the molding compound layer 60. The exposed portionsof the copper posts 52, 53 and 54 are electroplated to formelectroplated regions. When the voltage regulator module 2 on the systemboard undergoes a reflow soldering process, the electroplated regionscan provide lateral wetting capability. Consequently, the weldingstrength of the combination between the voltage regulator module 2 andthe system board is enhanced.

In an embodiment, the height of the magnetic core assembly 30, theheight of the first copper post 51, the height of the second copper post52 and the height of the third copper post 53 are equal. Moreover, themagnetic core assembly 30, the first copper post 51, the second copperpost 52 and the third copper post 53 are welded on the same inner layer80 of the printed circuit board 22. It is noted that the heights of themagnetic core assembly and the copper posts may be different from eachother and the magnetic core assembly and the copper posts may be fixedon different inner layers.

In this embodiment, the magnetic core assembly 30 is disposed on theinner layer 80 of the printed circuit board 22. Consequently, the secondsurface 22 b of the printed circuit board 22 has more layout area forarranging the first bonding pad 51 a, the second bonding pad 52 a, thethird bonding pad 53 a and the fourth bonding pad 54 a. Since the areaof at least one of the first bonding pad 51 a, the second bonding pad 52a, the third bonding pad 53 a and the fourth bonding pad 54 a isincreased, the welding area and the welding strength between thecorresponding bonding pad and the system board are increased and theaverage force on the voltage regulator module is reduced. In addition,the weight withstood by the unit welding surface is reduced, the purposeof diffusing current is achieved, and the power loss is reduced.

From the above descriptions, the present disclosure provides the voltageregulator module. The switch elements and the magnetic core assembly aredisposed on two opposite sides of the printed circuit board. The firstsurface of the printed circuit board is encapsulated. The magnetic coreassembly and the copper posts are embedded within the printed circuitboard. The conductors formed on the second surface of the printedcircuit board are welded on the system board. Alternatively, the copperposts are disposed on the circuit board, encapsulated by a double-sidedplastic molding process, and welded on the system board. When thevoltage regulator module on the system board undergoes a reflowsoldering process, the inner components to be heated are not detached orshifted. In other words, the process of fabricating the voltageregulator module is simplified. When compared with the conventionalvoltage regulator module, the size of the voltage regulator module ofthe present disclosure is reduced.

While the disclosure has been described in terms of what is presentlyconsidered to be the most practical and preferred embodiments, it is tobe understood that the disclosure needs not be limited to the disclosedembodiment. On the contrary, it is intended to cover variousmodifications and similar arrangements included within the spirit andscope of the appended claims which are to be accorded with the broadestinterpretation so as to encompass all such modifications and similarstructures.

What is claimed is:
 1. A voltage regulator module for powering a load, comprising: a switch circuit assembly, comprising: two switch circuits, wherein respective input terminals of the two switch circuits are connected with each other in parallel; and an input capacitor, wherein the input capacitor is electrically connected with the respective input terminals of the two switch circuits in parallel and disposed between the two switch circuits; and a magnetic assembly, comprising: a core assembly; and a plurality of conductive members, wherein the plurality of conductive members have at least one first conductive member, at least one second conductive member and at least one third conductive member, and the at least one first conductive member and the at least one third conductive member are configured to deliver an electric energy, and the at least one second conductive member is configured to deliver a signal, one end of each of the plurality of conductive members is electrically connected with corresponding one of the two switch circuits, and the other end of the at least one first conductive member and the at least one third conductive member of the plurality of conductive members is electrically connected with the load; wherein the switch circuit assembly and the magnetic assembly are stacked with each other.
 2. The voltage regulator module according to claim 1, wherein the at least one first conductive member comprises two first conductive members, one end of each of the two first conductive members is connected with the corresponding one of the two switch circuits, and the other end of each of the two first conductive members is defined as a positive output terminal of the voltage regulator module.
 3. The voltage regulator module according to claim 2, wherein the core assembly comprises two openings, and the two first conductive members penetrate through corresponding one of the two openings, respectively.
 4. The voltage regulator module according to claim 1, wherein the at least one second conductive member comprises two second conductive members, one end of each of the two second conductive members receives a pulse width modulation signal, wherein a phase difference between the pulse width modulation signal received by one of the two second conductive members and the pulse width modulation signal received by the other of the two second conductive members is 180 degree, and the switch circuit connected with the corresponding second conductive member is controlled according to the pulse width modulation signal received by the corresponding second conductive member.
 5. The voltage regulator module according to claim 1, further comprising a conductor assembly, wherein the switch circuit assembly, the magnetic assembly and the conductor assembly are stacked with each other in sequence.
 6. The voltage regulator module according to claim 5, wherein the conductor assembly comprises a positive output terminal conductor, a positive input terminal conductor and a negative output terminal conductor, wherein the positive output terminal conductor is electrically connected with the corresponding first conductive member, and the positive input terminal conductor and the negative output terminal conductor are electrically connected with the corresponding third conductive member, respectively; wherein an area of any conductor of the positive output terminal conductor, the positive input terminal conductor and the negative output terminal conductor is larger than or equal to a surface area of the corresponding first conductive member or the corresponding third conductive member, respectively.
 7. The voltage regulator module according to claim 6, wherein the conductor assembly further comprises a signal terminal conductor, electrically connected with the corresponding second conductive member.
 8. The voltage regulator module according to claim 1, wherein the two switch circuits are substantially symmetric with each other.
 9. The voltage regulator module according to claim 1, wherein the two switch circuits are substantially centrosymmetric along a diagonal line of the switch circuit assembly.
 10. The voltage regulator module according to claim 1, wherein each of the two switch circuits is electrically connected with the magnetic assembly, and each of the two switch circuits and the magnetic assembly are collaboratively served as one phase buck circuit of the voltage regulator module.
 11. The voltage regulator module according to claim 1, wherein each of the two switch circuits comprises a first switch and a second switch, and the first switch is electrically connected with the second switch in series.
 12. A voltage regulator module, comprising: a switch circuit assembly comprising a switch circuit; a magnetic assembly comprising at least one core assembly and at least one first conductive member, wherein the core assembly has an opening, and the at least one first conductive member penetrates through the opening; and a conductor assembly, wherein the switch circuit assembly, the magnetic assembly and the conductor assembly are stacked with each other in sequence; wherein one end of the at least one first conductive member is electrically connected with corresponding switch circuit, and the other end of the at least one first conductive member is electrically connected with the conductor assembly; wherein an inductor is defined by the at least one first conductive member penetrating through the opening and the core assembly collaboratively, and the inductor is embedded in a printed circuit board.
 13. The voltage regulator module according to claim 12, wherein two ends of the at least one first conductive member are electrically connected with the conductor assembly and corresponding one of the two switch circuit through at least one via, respectively.
 14. The voltage regulator module according to claim 13, wherein two ends of the at least one first conductive member are electrically connected with the conductor assembly and the corresponding one of the two switch circuits through a same via.
 15. The voltage regulator module according to claim 13, wherein one end of the at least one first conductive member is electrically connected with the corresponding one of the two switch circuits through a first via, and the other end of the at least one first conductive member is electrically connected with the conductor assembly through a second via, wherein the first via is different from the second via.
 16. The voltage regulator module according to claim 15, wherein the first via and the second via are straight.
 17. The voltage regulator module according to claim 15, wherein the first via and the second via are stepped.
 18. The voltage regulator module according to claim 13, wherein the via is straight or stepped.
 19. The voltage regulator module according to claim 12, wherein the magnetic assembly comprises a second conductive member and a third conductive member, and two ends of each conductive member of the second conductive member and the third conductive member are electrically connected with the conductor assembly and corresponding one of the two switch circuits through at least one via, respectively.
 20. The voltage regulator module according to claim 12, wherein the switch circuit assembly further comprises an input capacitor electrically connected with respective input terminals of the two switch circuits.
 21. The voltage regulator module according to claim 12, wherein the conductor assembly comprises at least one positive output terminal conductor, electrically connected with the at least one first conductive member, and an area of the at least one positive output terminal conductor is larger than or equal to a surface area of the at least one first conductive member.
 22. The voltage regulator module according to claim 19, wherein the conductor assembly comprises a positive input terminal conductor and at least one negative output terminal conductor, wherein the positive input terminal conductor or the at least one negative output terminal conductor is electrically connected with the third conductive member, wherein an area of the positive input terminal conductor or an area of the at least one negative output terminal conductor is larger than or equal to a surface area of the third conductive member.
 23. The voltage regulator module according to claim 12, wherein the switch circuit comprises a first switch and a second switch, and the first switch is electrically connected with the second switch in series.
 24. The voltage regulator module according to claim 12, wherein the magnetic assembly further comprises two second conductive members, and one end of each of the two conductive members receives a pulse width modulation signal, wherein a phase difference between the pulse width modulation signal received by one of the two second conductive members and the pulse width modulation signal received by the other of the two second conductive members is 180 degree, and the switch circuit connected with the corresponding second conductive member is controlled according to the pulse width modulation signal received by the corresponding second conductive member. 